We've updated our Privacy Policy to make it clearer how we use your personal data.

We use cookies to provide you with a better experience. You can read our Cookie Policy here.

Advertisement
Boosting the Cell's Power House
News

Boosting the Cell's Power House

Boosting the Cell's Power House
News

Boosting the Cell's Power House

When assembled into a supercomplex, the two parts of CIII2CIV are held together by a molecule that acts like a fishhook. This optimizes the cell metabolism. Credit: Verena Resch Luminous Lab / IST Austria
Read time:
 

Want a FREE PDF version of This News Story?

Complete the form below and we will email you a PDF version of "Boosting the Cell's Power House "

First Name*
Last Name*
Email Address*
Country*
Company Type*
Job Function*
Would you like to receive further email communication from Technology Networks?

Technology Networks Ltd. needs the contact information you provide to us to contact you about our products and services. You may unsubscribe from these communications at any time. For information on how to unsubscribe, as well as our privacy practices and commitment to protecting your privacy, check out our Privacy Policy

In order to fulfill their many tasks, cells need energy. In the cell's power plants, known as mitochondria, the energy contained in our food is converted into the molecule ATP. It serves as a kind of fuel that drives most cellular processes – from muscle contraction to the assembly of our DNA. Professor Leonid Sazanov and Irene Vercellino are now the first scientists to precisely show what a protein assembly essential for this process looks like in mammalian cells.

Like a fishhook


Using cryo-electron microscopy, a technique that allows researchers to look at extremely small samples in their natural state, first author Irene Vercellino and Prof. Sazanov show the exact structure of the so-called supercomplex CIII2CIV. This assembly of protein building blocks pumps charged particles, protons, through the mitochondrial membrane, which is needed to start the energy conversion process in the cells. It therefore fulfills a similar task as the starter battery of cars. Up to now, this supercomplex has only been described in plant and yeast cells where it takes on a very different form, as the researchers now discovered. In order to understand how exactly energy production works in animal cells like our own, the scientists now took a close look at mice and sheep cells and were surprised.

“Nobody could have predicted the way SCAF1 acts,” says Sazanov. Previous studies already showed that the molecule SCAF1 plays a role in assembling the two protein complexes that together form supercomplex CIII2CIV. Instead of interacting with the two protein complexes on the surface only, the molecule goes deep inside complex III while being attached to complex IV. “It is like a hook swallowed by a fish. Once it’s swallowed it can’t get out,” the structural biologist explains.

Close, but not too close


Furthermore, the scientists show that supercomplex CIII2CIV takes on two different forms – a locked and an unlocked or mature one. “In its locked state some parts of complex III are still missing and the interaction between the two complexes is very intimate,” describes Sazanov. Once it is fully assembled, however, the two complexes are connected by SCAF1 without getting in each other’s way. “In order to fulfill its tasks, complex III probably prefers to be free from interference in its movements,” the Belarusian-British scientist assumes.

Being assembled into a supercomplex, on the other hand, speeds up their chemical reactions, which has great advantages for the animal.  It has been shown, that mice and zebrafish missing the SCAF1 molecule are significantly smaller, less fit, and less fertile. In their recent study, Vercellino and Sazanov describe the molecule’s role in forming supercomplex CIII2CIV, which optimizes the cellular metabolism. It has been the final piece of the puzzle: together with their previous studies, Sazanov and his team now determined the structures of all supercomplexes in mammalian mitochondria. The team is thus laying the foundation for new treatments for mitochondrial disease.

Reference: Vercellino I, Sazanov LA. Structure and assembly of the mammalian mitochondrial supercomplex CIII2CIV. Nature. 2021:1-4. doi: 10.1038/s41586-021-03927-z

This article has been republished from the following materials. Note: material may have been edited for length and content. For further information, please contact the cited source.


Advertisement